Replace direct CREATE EXTENSION commands with conditional checks to avoid
permission errors on Azure PostgreSQL Flexible Server where only
azure_pg_admin members can create extensions.
- Check pg_extension table before attempting to create vector extension
- Apply same fix to pgcrypto extension for consistency
- Allows following least privilege principle for database users
Fixes#12453
Resolves issue where OpenAPI specs with array query parameters were generating
invalid OpenAI function schemas missing the required 'items' property, causing
400 Bad Request errors from OpenAI.
The fix ensures that when converting OpenAPI parameter schemas to OpenAI function
schemas, array parameters properly include their 'items' property definition.
Fixesopen-webui/open-webui#14115
Rain6435